In a switching device with two controlled phases, in which each phase is associated with a respective printed circuit board assembly with at least one component to be cooled on a heat sink, the heat sink has a T-shaped cross section transversely with respect to its extent direction. In at least one embodiment, the printed circuit board assemblies are arranged on both sides of the center limb of the heat sink, with the components of the two printed circuit board assemblies facing one another and resting on in each case one side of the center limb.